Each of the three Wrangler transmissions has a different correct answer here, and the vehicle's use pattern matters as much as the failure itself. NSG370 Manual — in-house rebuild is usually correct: The NSG370 is a straightforward gear-driven unit with no electronics. Parts availability is good, rebuild complexity is moderate, and a competent manual transmission tech can complete a rebuild in 6–8 hours. The key decision point is shaft and bearing condition. If the input shaft bearing has failed, inspect the input shaft for scoring at the bearing journal. A scored shaft needs replacement — the bearing will fail again on a damaged journal. Shaft replacement adds $120–$180 to parts cost but is the correct repair. Used NSG370 units from salvage are viable for low-mileage cores only — verify the synchronizer condition before committing to a used unit as a core.
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